Does the Increase in Spine Surgery Reflect an Increase in Disease?
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Does the Increase in Spine Surgery Reflect an Increase in Disease?. Sohail K. Mirza, MD MPH Professor, Department of Orthopedics and Joint Professor, Department of Neurological Surgery University of Washington. NASS Format. X. UW Tech Transfer (Synthes). X. X. X. X. X. X. X.

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Does the Increase in Spine Surgery Reflect an Increase in Disease?

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Does the Increase in Spine Surgery Reflect an Increase in Disease?

Sohail K. Mirza, MD MPH

Professor, Department of Orthopedics and

Joint Professor, Department of Neurological Surgery

University of Washington


NASS Format

X

UW Tech Transfer (Synthes)

X

X

X

X

X

X

X

Depuy, Surgical Dynamics, Synthes

(to UW Dept. of Orthopedics)

X

X

X

X

X

Depuy, Synthes (to Dept of Orthop)

X

X


Disclosure

  • I hold the University of Washington Surgical Dynamics Endowed Chair for Spine Outcomes Research (approx $90k in 2006).

  • I receive royalties for surgical drills licensed by Synthes Spine through UW Office of Technology Transfer (approx. $16k in 2006).

  • UW Department of Orthopedics receives spine fellowship support, research support, and endowments from Synthes Spine and Depuy Spine. I work with the spine fellows and am involved with two of the research projects supported by these funds.

  • I prepared all the slides.

Sohail K. Mirza, MD, MPH

Professor, Department of Orthopedics and Sports Medicine

and Department of Neurological Surgery, University of Washington

Harborview Medical Center, Box 359798

325 Ninth Avenue

Seattle, WA 98104

Email: [email protected] Tel: 206 731 3658 Fax: 206 731 3227


Does the increase in spine surgery reflect an increase in disease?

no


Back Pain

1,865,196 results on 5/17/2002

707,000,000 results on 6/ 5/2007

26,100,000 results on 1/15/2008


New Technologies

Resolution of pedicle screw litigation

New posterior fixation devices

New anterior fixation devices

Cages

Bone graft substitutes

Bone morphogenetic proteins

Minimally invasive spine surgery

Computer-assisted surgery

Artificial discs


New Clinical Knowledge: RCTs

  • Fusion results in better pain and function outcome in patients with spondylolisthesis.

  • Fusion with instrumentation results in a higher fusion rate.

  • Instrumentation is associated with a higher complication rate.

  • Artificial disc replacement may avoid complications of fusion.


Normal

Degeneration


Biochemical Changes

  • Water content

  • Proteoglycan content

  • Chondroitin to sulfate ratio

  • Collagen network


Collagen

Repetitive Sequence (GLY – X – Y )

X: proline

Y: hydroxyproline

Triple helix

Tryptophan substitution?


Ala-KokkoScience 1999JAMA 2001 Spine 2002

Col9A2: Glutamine  Tryptophan

Disc disease 6/157 (vs. 0/174 controls)

COL9A3: Arginine  Tryptophan

Disc disease 12% (vs. 5% controls)

Trp allele  3X risk for disc disease


Association with Collagen IX Tryptophan Alleles

Matsui, Mirza, Eyre JBJS-B 2004


Association with Collagen IX Tryptophan Alleles


Spinal Stenosis with Spondylolisthesis


Potential Physiological Basis for Disc-associated Back Pain

  • Initiation of a chemotactic response

  • Vascular ingrowth

  • Increased sensory innervation

  • Endplate cartilage defects

  • Inflammation


Variation


Ratio of Back Surgery Rates

Deyo, Mirza CORR 2006


Variation in Lumbar Fusion Rates

Per 1000 Medicare

Enrollees 2002-2003

Weinstein, Lurie et al Spine 2006


Deyo, Mirza CORR 2006


Variation in Lumbar Fusion Rates

Rate Per 1000 Medicare Enrollees

Weinstein, Lurie et al Spine 2006


Variation in Lumbar Surgery Rates

LaminectomyFusion

Variation in

Regional Rates8X20X

Weinstein, Lurie et al Spine 2006


Causes of Variation

  • Lack of scientific evidence

  • Financial Incentives and Disincentives

  • Clinical Training and Professional Opinion

  • New technology

Weinstein, Lurie et al Spine 2006


Growth


Procedure Comparisons (2001)

Deyo, Nachemson, Mirza NEJM 2004


Annual Number of Operations in U.S.

Data from National Inpatient Sample, HCUP/AHRQ

Deyo, Nachemson, Mirza NEJM 2004


Inpatient Medicare Reimbursement

Weinstein, Lurie et al Spine 2006


Inpatient Medicare Reimbursement

19922003

Rate of Lumbar Fusion30 per 100k110 per 100k

Spending for Lumbar Fusion$75 million$482 million

Percent Spending for Fusion14%47%

Weinstein, Lurie et al Spine 2006


Deyo, Mirza et al Spine 2005


Deyo, Mirza et al Spine 2005


Deyo, Mirza et al Spine 2005


Deyo, Mirza et al Spine 2005


Deyo, Mirza et al Spine 2005


Deyo, Mirza et al Spine 2005


Office Visits for Back Pain

Deyo, Mirza, Martin Spine 2006


National Health Interview Survey 2002

Deyo, Mirza, Martin Spine 2006


National Health Interview Survey 2002

Deyo, Mirza, Martin Spine 2006


National Health Interview Survey 2002

Deyo, Mirza, Martin Spine 2006


US Prevalence of Back Pain

Deyo, Mirza, Martin Spine 2006


US Prevalence of Back Pain

Deyo, Mirza, Martin Spine 2006


Potential Financial Conflicts of Interest


Favorable Results in Industry-Sponsored Research

SponsorOdds Ratio95% CI

Sponsor of study3.62.6 to 4.9

For-profit organizations5.32.0 to 14.4

Manufacturer of drugs8.01.1 to 53.2

Spinal device manufacturer3.32.4 to 4.5

Jacobs, Galante, Mirza, Zdeblick JBJS 2006


Favorable Results

FieldIndustry-fundedIndependent

Spine73%44%

Hip93%37%

Knee75%20%


“Surgeons have often touted procedures that ultimately proved to be disappointing.”

April 8, 2002


April 8, 2002

“Trisha Bryant assumed that the procedures her surgeon recommended were necessary and had been validated by research. I, too, made that assumption….If Trisha had explored the medical literature, however, she would have discovered that every aspect of her case– the interpretation of the MRI scan, the diagnosis of spinal instability, the rationale for fusing vertebrae, the impending discography– was controversial…”


April 8, 2002

“… within the surgical profession there’s a curious gap between rhetoric and reality.”

“Spinal instability is routinely given as a diagnosis to these patients with chronic lower-back pain. It is a term used to justify an operation. And it is a great diagnosis, because it can’t be directly disproved.”

Surgeon who performs two to three spinal fusions a week.

“Each approach to diagnosis and treatment is essentially a franchise, and there are too many franchises battling.”

Seth Waldeman

Pain Medicine, HSS


Conclusions

  • Biological basis for “discogenic back pain” is not known.

  • Rates of lumbar fusion for chronic back pain have increased without increase in prevalence of back pain.

  • Investigator-sponsor financial conflicts are common.


Thank you.


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